Auger arrangement for trenching machine



Oct. 9, 1962 F. c. KIECHEL ET AL 3,057,089

AUGER ARRANGEMENT FOR TRENCHING MACHINE I Filed Nov. 17, 1961 2 Sheets-Sheet l INVENTORS FRED C. KIECHEL BY RAY STRAW 1962 F. c. KIECHEL ET AL 3,057,089

AUGER ARRANGEMENT FOR TRENCHING MACHINE Filed Nov. 17, 1961 2 Sheets-Sheet 2 INVENTORS Fneo C. KIECHEL RAY .STRAW Patented Oct. 9, 1962 3,057,089 AUGER ARRANGEMENT FOR TRENCHING MACHINE Fred C. Kiechel and Ray Straw, Auburn, Nebr., assignors to Auburn Machine Works, Inc., Auburn, N ebr., a corporation of Nebraska Filed Nov. 17, 1961, Ser. No. 153,039 3 Claims. (CI. 37-90) The present invention relates to trenching machines and more particularly to an improved auger arrangement for sweeping the elevated dirt into a ridge parallel to the trench.

In Schmidt Patent 2,915,077 there is disclosed a trencher having a digging boom with augers powered by a digger chain for the purpose of sweeping the dirt clear of the trench and for depositing it in ridges running parallel to the trench. For this purpose the anger is provided with two flights, one screwing in onedirection and the other in the opposite direction so that both augers are effective to sweep the dirt outwardly away from the trench. This arrangement has been employed in various commercial trenchers. The need has been recognized in the past for piling up the elevated dirt all on one side of the trench as, for example, where it is necessary to dig a trench closely adjacent an existing building, or in the digging of footingswhere the dirt on the far side of the trench may be inaccessible to a backfilling tractor and blade, but it has not been possible in the past to accomplish this, using an auger type of dirt conveyor.

Accordingly, it is an object of the present invention to provide a trench digging machine having an auger type conveyor and in which all of the elevated dirt is piled in a ridge on one side of the trench. It is another object to provide an auger conveyor in a trench digging machine in which the dirt elevated by the digger blades is deposited on both sides of the trench but in which the conveyor on one side acts effectively to transfer the elevated dirt from one side of the trench to the other, sweeping the surface of the ground on the non-depositing side free of loose dirt.

It is another object of the present invention to provide an auger conveying arrangement for a trencher which is readily applied to trench digging machines of conven tional design and without necessity for any mechanical modification.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIGURE 1 is a general perspective of a trench digging machine with an anger conveyor constructed in accordance with th present invention.

FIG. 2 is a fragmentary vertical section taken through the machine of FIG. 1 and showing the digging boom extending down into the ground.

FIG. 3 is a fragmentary rear elevation corresponding to FIGS. 1 and 2.

FIG. 4 is a close up view of the rear end of the trenching machine showing the digger boom in semi-upraised position.

FIG. 5 is a fragmentary section taken through one of the flights of the auger conveyor and showing the manmy in which the flight is secured to the shaft.

While the invention has been described in connection with a preferred embodiment, it will be understood that we do not intend to be limited to the particular embodiment but, on the contrary, we intend to cover the various alternative and quivalent constructions falling within the spirit and scope of the appended claims.

Turing now to the drawings there is shown a typical trench digging machine 10. The assembly includes a farm type tractor 11 having rear supporting wheels 12, 13.

Secured to the rear end of the tractor is a trenching unit having a frame 15 mounting a digging boom 16, the digging boom being vertically swingable on a transverse shaft 17 between an upraised Or transport position and the digging position shown in FIGS. 13. Trained about the boom is a digger chain 20 having digger bits 21. At the upper end of the boom the chain engages a drive sprocket 23 which is coupled, by means not shown, to the tractor engine. Means are, moreover, provided for rotating the rear wheels of the tractor at a slow forward speed so that as the tractor creeps forwardly the digger bits 21 act upon the ground to form a trench, the width of the trench depending upon the span of the digger blades.

The dirt which is brought to the surface by the digger bits is ejected upwardly with some force as shown in FIG. 2. A batfle 25 is preferably interposed in the path of movement of the dirt a described in McIninch Patent 2,748,054. After striking the baffle 25 the dirt drops downwardly onto the ground, half on one side of the trench and half on the other.

For the purpose of sweeping the loose dirt clear of the trench for later backfill, it is conventional in trench digging machines of the type shown to provide auger conveyors which are mounted upon the boom 16 and which are driven by the adjacent run of the digger chain. Two augers are preferably employed for dirt conveying purposes. The first auger generally indicated at 30 has flights 31, 32'mounted upon a shaft 33 which is journaled in a bracket 34 secured to the underside of the boom, with the bracketbeing centrally relieved to accommodate a sprocket wheel 35 which meshes with the lower run of the chain. Similarly in the rear position there is provided an auger 40 having flights 41, 42 secured to a transverse shaft 43 which is journaled in an upper bracket 44. Such bracket may be identical to the bracket 34, accommodating a sprocket wheel 45 which, in this case, engages the upper run of the chain. The brackets 34, 44 are adjustably positionable along the boom. For a given depth of trench and angle of boom the adjustment is such that all of the auger flights are in grazing contact with the surface of the ground.

In accordance with the present invention, instead of employing oppositely directed flights at the respective ends of the auger shafts, flights are employed which are all of the same hand so that the augers on one side of the trench act to redeposit the elevated dirt back into the trench to be acted upon, again, by the chain and the digger bits. In the present embodiment all four of the flights 31, 32 and 41, 42 are right hand flights and rotation of the auger shaft is left hand, or counterclockwise, when viewed from the right hand side of the machine. As a result of the action of the diggers and chain, loose, elevated dirt is deposited ahead of the augers as indicated at 51 in FIG. 3, on the right hand side of the trench and as indicated at 52 on the left hand side of the trench. Since both auger flights, under the conditions stated, tend to sweep to the left, the loose dirt 5 1 is swept back into the trench as indicated by the arrow 53. However, the dirt 52 is deposited in a ridge 54 located outboard of the tractor. The net result is that the right hand of the trench is kept completely clear of dirt so that all of the backfill may be accomplished by a tractor and blade operating on the left hand side of the trench. This is particularly valuable where the trench is formed next to a building wall or the like indicated at 55 (FIG. 3) and whereby backfilling from such side would be diflicult or impossible. The arrangement is also advantageous where the trenching machine is employed for digging footings and where the area contained Within the footings may not be accessible to a tractor. A further advantage of depositing the dirt in a single ridge 54 is that backfill is more easily accomplished than where two separate ridges must be acted upon to deposit a given amount of dirt.

It might be assumed that depositing half of the dirt back in the trench would result in a slow and ineflicient operation or result in some of the dirt being left at the bottom of the trench. However, experience shows that this does not occur. It is found, on the contrary, that conventional trenching speeds for a given set of conditions may be maintained and there is no sacrifice in digging efliciency. This is explained in part by the fact that the dirt moving capacity of the augers apparently exceeds the rate at which augers are required to convey dirt under normal trenching conditions. Because of the scavenging action of the rapidly moving chain and bits, it is found that the dirt which is swept back into the trench does not travel more than a short distance before it is acted upon by the bits and again propelled to the surface. While it is doubtless true that a given piece of dirt may be acted upon in this fashion several times before being successfully deposited on the left hand side of the trench, nevertheless this does not appear to produce any noticeable additional load on the trenching machine.

While the invention has been described above as applied to an arrangement having a total of four flights, the invention is not limited thereto but would include an arrangement having only a single auger equipped with unidirectional flights on the left and right hand side. While the area is not swept quite as clean where only a single anger is used, nevertheless this will be found adequate for most purposes.

For maximum flexibility of operation, it is one of the features of the invention that the auger flights may be interchangeably employed in any one of four positions. Referring to FIG. 5 and taking FIG. 1 by way of example, it will be seen that the flight consists of a helically curved plate of metal secured by welding to a central hollow tube. The flight is secured to the auger shaft 33 by means of a pin 60 fitted into registering holes 61 in the tube and in the end of the auger shaft 33. The same auger flight may thus be used on the left hand side of the machine simply by retracting the pin 60, by telescoping the flight over the left hand end of the shaft 33 and by replacing the pin.

7 Since the single ridge of dirt produced by the present arrangement is proportionately larger than the dual ridges formed using the conventional arrangement, my invention in one of its aspects contemplates making the leading auger on the discharge side of greater length than the standard sized auger which follows it. Consequently, depositing of the dirt in the ridge takes place in two steps. The bulk of the dirt is moved outwardly to form a ridge 5'4, by the leading auger 32. The remaining dirt is not moved into the center of the ridge but, rather, is simply transported to the base of the ridge so that the ridge does not have to be churned or dislodged upon passage of the second auger. It is found that such arrangement tends to form a neat ridge while minimizing the amount of power required to drive the augers,

As a still further modification the trailing auger on the non-discharge side may, if desired, be omitted entirely since the forward auger produces an adequate sweeping function,

We claim as our invention:

1. In a trench digging machine the combination comprising a tractor, a digger boom mounted on the rear end of the tractor and swingable about a transverse axis from an upraised position to a lowered digging position, a digger chain trained about said boom and drivingly coupled to the tractor engine, and an auger assembly having transverse shaft means rotatably mounted on said boom and having auger flights on both ends thereof drivingly coupled to the digger chain and in grazing contact with the ground when the boom is in digging position for lateral transport of the dirt deposited on the surface of the ground by the digger chain, the flights of the auger assembly being of the same directivity so that one of the flights acts to sweep the elevated dirt which it engages back into the trench while the other flight acts upon the elevated dirt which it engages to form the same into a single ridge parallel to the trench.

2. In a trench digging machine the combination comprising 'a tractor, adigger boom mounted on the rear end of the tractor and swingable about a transverse axis from an upraised position to a lowered digging position, a digger chain trained about said boom and drivingly coupled to the tractor engine, and a pair of augers having transverse shafts rotatably mounted on said boom one behind the other, each auger having flights on both ends thereof drivingly coupled to the digger chain and in grazing contact with the ground when the boom is in digging position for lateral transport of the dirt deposited on the surface of the ground by the digger chain, said flights being of the same directivity so that one of the flights acts to sweep the elevated dirt which it engages back into the trench while the other flight acts upon the elevated dirt which it engages to discharge the same into a single ridge parallel to the trench, the forward auger on the discharge side having a length which exceeds the rear auger on such side so that the rear auger sweeps the dirt which it engages up to the base of the ridge formed by the forward auger.

3. In a trench digging machine the combination comprising a tractor, a digger boom mounted on the rear end of the tractor and swingable about a transverse axis from an upraised position to a lowered digging position, a digger chain trained about said boom and drivingly coupled to the tractor engine, and an anger assembly having disengageable flights on the left and right hand sides drivingly coupled to the digger chain and in grazing contact with the ground when the boom is in digging position for lateral transport of the dirt deposited on the surface of the ground by the digger chain, said flights being of the same directivity so that one of the flights acts to sweep the elevated dirt which it engages back into the trench while the other flight acts upon the elevated dirt which it engages to form the same into a single ridge parallel to the trench.

Model M Ditch-Witch Trencher; description contained on pages 124 and 125 of July 1957 publication of Civil Engineering (volume 2.7, No. 7). 

